The linear presentation of audio or video is inefficient because it is tedious to refer back in order to recover a train of thought or search for previous mater

The linear presentation of audio or video is inefficient because it is tedious to refer back in order to recover a train of thought or search for previous material. Some MOOC courses are given primarily by video lectures with a side-by-side transcript. I can read faster than the audio, even with the audio set to 1.5 X speed. It's also easier to skip back and re-scan the transcript. Reading the transcript at the same time as listening to the audio enhances retention.